When Should I Call the Doctor/take Pregnancy Test

I have been on the pill for over 5 years with a couple months off during that time period. Since i've been on the pill, my period has been very regular. I start at the same time every month with in a few hours. I am three days late now. I've had a bad cold, which has shortened my periods when i've had illnesses in the past. I admit that over the past few months that I haven't taken my pills necessarily on time because i've had some problems with nausea, but I haven't missed any. My husband and I want children, but we were planning on waiting a year or two more. If I am pregnant, we would want to have the baby though. When can I take a pregnancy test that would be accurate? Should I call the doctor regardless since I never miss a period? I am suppose to start up the regular pills again on sunday. I've heard that this can be harmful to a prenancy so should I not take them if I am still not bleeding at all.